Catalogue Search | MBRL
Are you sure you want to remove the book from the shelf?
{{itemTitle}}
17,842
result(s) for
"Prestressed concrete"
Sort by:
Experimental Study on Concrete Pile-to-Cap Connection Behavior
Current design assumptions for precast, prestressed concrete piles embedded in cast-in-place (CIP) pile caps or footings vary across states, leading to inconsistencies in engineering practices. Previous studies suggest that short embedment lengths (0.5 to 1.0 times the pile diameter) can develop approximately 60% of the bending capacity of the pile, with full fixity potentially achieved at shorter embedment lengths than current design specifications due to confinement stresses. This study experimentally evaluates 10 full-scale pile-to-cap connection specimens with varying embedment lengths, aiming to investigate the required development length for full bending capacity. The findings demonstrate that full bending capacity can be achieved at the pile-to-pile cap connection with shallower embedment than code provisions, challenging existing design standards and highlighting the need for more accurate guidelines for bridge foundation design. Keywords: pile embedment length; pile-to-cap connections; precast, prestressed concrete pile.
Journal Article
Research on bending tests and modified calculation of flexural strength for hybrid reinforced pipe piles
To investigate the influence of ordinary reinforcement on the bending moment capacity of prestressed high-strength concrete (PHC) pipe piles, this study conducted flexural tests on four prestressed reinforced concrete (PRC) pipe piles with hybrid reinforcement and two PHC pipe piles. Through comparative analysis of their bending moment capacity, deformation characteristics, and crack propagation patterns, the enhancement mechanism of ordinary reinforcement on the bending moment capacity of PHC pipe piles was revealed. Based on the correspondence between the experimentally measured coefficient of relative compression zone area
η
and the theoretical value
α
, the existing calculation formula for the ultimate bending moment capacity of pipe piles was modified. The results indicate that increasing the rebar diameter enhances deformation resistance and alters the deflection development pattern. The use of ordinary reinforcement improves the bending moment capacity of PRC pipe piles by 36% to 51% compared to PHC pipe piles. In contrast to PHC pipe piles, PRC pipe piles exhibit a transition from sparse, wide cracks to dense, narrow cracks, demonstrating that ordinary reinforcement effectively restrains crack width propagation, thereby improving the ductility and service performance of pipe piles. The modified ultimate bending moment calculation formula for pipe piles significantly enhances computational accuracy and reduces dispersion while maintaining safety margins. These research findings provide a reliable theoretical basis for the optimized design and engineering application of PRC pipe piles.
Journal Article
Structural Health Monitoring Based on Acoustic Emissions: Validation on a Prestressed Concrete Bridge Tested to Failure
The increasing number of bridges approaching their design life has prompted researchers and operators to develop innovative structural health monitoring (SHM) techniques. An acoustic emissions (AE) method is a passive SHM approach based on the detection of elastic waves in structural components generated by damages, such as the initiation and propagation of cracks in concrete and the failure of steel wires. In this paper, we discuss the effectiveness of AE techniques by analyzing records acquired during a load test on a full-size prestressed concrete bridge span. The bridge is a 1968 structure currently decommissioned but perfectly representative, by type, age, and deterioration state of similar bridges in operation on the Italian highway network. It underwent a sequence of loading and unloading cycles with a progressively increasing load up to failure. We analyzed the AE signals recorded during the load test and examined how far their features (number of hits, amplitude, signal strength, and peak frequency) allow us to detect, quantify, and classify damages. We conclude that AE can be successfully used in permanent monitoring to provide information on the cracking state and the maximum load withstood. They can also be used as a non-destructive technique to recognize whether a structural member is cracked. Finally, we noticed that AE allow classifying different types of damage, although further experiments are needed to establish and validate a robust classification procedure.
Journal Article
Monitoring and identification of wire breaks in prestressed concrete cylinder pipe based on distributed fiber optic acoustic sensing
Prestressed concrete cylinder pipes (PCCPs) have become increasingly competitive in pipeline transportation due to several advantages such as high pressure-bearing capacity and good durability. Unfortunately, corrosion and deterioration would cause certain PCCPs to fail after an amount of time in service. To assess the condition of pipelines and to eliminate catastrophic consequences, long-term monitoring is necessary. In this study, a novel method based on distributed acoustic sensing (DAS) technology, was presented to monitor and identify wire breaks in PCCP under different conditions such as corrosion and hydrogen embrittlement. The findings revealed that DAS has a recognition accuracy for vibration, particularly wire breaks, and captures wire breaks and noise at multiple locations in a variety of environments quickly and efficiently. Wire break signals in different environments have both similarities and differences. From the time-domain perspectives of amplitude, duration, short-time zero-crossing rate, and short-time energy, the wire’s break and noise could be effectively discriminated. The wires will break without warning after reaching the ultimate bearing capacity, which is related to the internal water pressure. The nature of its break is the release of internal energy, independent of the factors that make it fracture, such as substandard wire quality and erosion.
Journal Article
Prestressing Analysis of Large Three-Dimensional Systems and Prestress Management (Open Source)
A three-dimensional (3-D) finite element method for prestressing and seating analysis has been developed. This method improves the accuracy of the results obtained using the widely adopted initial stress method and enables calculation of the seating loss effect, which is the final stress prediction of prestressing. Its application for large numbers of indeterminate-order structures is shown by comparing its calculation results with two-dimensional (2-D) conventional analysis, as well as with observed strain results for cables of an existing 462 m, six-span continuous bridge. With these considerations, a new management method of prestressing for jack force-diverting systems where the prestressing force does not focus uniquely on a design section was developed so that constructed prestressed concrete structures can be well-secured to comply with design objectives. Keywords: friction loss; large-scale prestressed concrete (PC) structure; prestressing analysis; prestressing management; set loss; three-dimensional (3-D) finite element method (FEM) analysis.
Journal Article
Material–Structural Synergy in Ultra-High-Performance Concrete-Optimized Prestressed Concrete Cylinder Pipes: Achieving Lightweight Design for Sustainable Infrastructure
While a large diameter is critical for maintaining water delivery efficiency in prestressed concrete cylinder pipes (PCCPs), excessive weight fundamentally limits their practical application. This study proposes a weight reduction strategy through material optimization and structural redesign. A full-scale experimental model of 2.8 m inner diameter PCCP was used to validate the finite element analysis method. Comparative numerical models were established to analyze strain/stress distribution in mortar coatings when using ultra-high-performance concrete (UHPC) versus conventional concrete cores. The key findings reveal that UHPC implementation reduces maximum coating strain by 20–30% compared to its conventional concrete counterparts. Multivariate linear regression analysis yielded a predictive formula that explicitly correlates the elastic modulus of the concrete core, core thickness, and mortar stress. This relationship permits the direct optimization of core thickness reductions according to the elastic modulus characteristics of UHPC materials. Verification through two case studies demonstrated a 25–35% core thickness reduction compared to the Chinese standard specifications while maintaining structural integrity, corresponding to an 18–22% total weight reduction. The proposed methodology successfully resolves the inherent weight limitation of conventional PCCPs while achieving equivalent hydraulic capacity, providing an effective pathway for sustainable infrastructure development through material-efficient design.
Journal Article
Computational analysis of curved prestressed concrete box-girder bridges using finite element method
The study employs finite element method to examine the effects of curve angle variations on the behavior of single and double-cell prestressed concrete box-girder bridges. A total of eighty bridge models were examined, featuring a range of curve angles from 0 to 60°, with increments of 12° between each model (0°, 12°, 24°, 36°, 48°, and 60°). The study revealed that bridges with curve angles of 24° or less exhibit minimal impact on forces, suggesting that they can be effectively treated as straight bridges for analytical purposes. The study revealed a marked change in structural response for bridges with curve angles greater than 24°, highlighting the influence of increased curvature on bridge behavior. A comprehensive evaluation was conducted to investigate the influence of changes in curve angles, span lengths, cell numbers, and span–depth ratios on structural forces and deflections under various load types, including dead, live, and prestressed loads. As the curve angle increases, a corresponding decrease in the flexural moment and vertical deflection is observed under prestressed loading conditions. Based on the analysis, it is reasonable to conclude that prestressed concrete box-girder bridges are best suited for applications involving higher curve angles.
Journal Article
Serviceability design charts for partially prestressed high-strength concrete girders
This paper presents the development of serviceability-based design charts for partially prestressed high-strength concrete (HSC) girders, with a focus on cracking and deflection performance. Partially prestressed girders, which serve as an intermediate design between fully prestressed and conventionally reinforced concrete, offer both structural efficiency and economic benefits. However, there is a notable gap in research regarding specific serviceability guidelines, particularly for controlling cracking and deflection in these girders. To address this gap, this study utilizes validated finite element models to investigate key variables, including the concrete compressive strength, prestressing forces, and non-prestressed reinforcement ratios. Parametric investigation provides insights into the impact of these factors on girder behavior under service loads, leading to the development of practical design charts. These charts allow for quick estimation of the optimal prestressing and reinforcement ratios that meet predefined serviceability limits, simplifying the design process for engineers. The proposed charts offer an accessible, efficient tool for optimizing material usage while ensuring compliance with serviceability criteria, making them highly valuable for the design of HSC girders in bridges and other infrastructures. Ultimately, this research enhances the usability of partially prestressed HSC girders, promoting more effective and economical designs in structural engineering practice.
Journal Article
Smart PZT-Embedded Sensors for Impedance Monitoring in Prestressed Concrete Anchorage
This study investigates the feasibility evaluation of smart PZT-embedded sensors for impedance-based damage monitoring in prestressed concrete (PSC) anchorages. Firstly, the concept of impedance-based damage monitoring for the concrete anchorage is concisely introduced. Secondly, a prototype design of PZT-embedded rebar and aggregate (so-called smart rebar–aggregate) is chosen to sensitively acquire impedance responses-induced local structural damage in anchorage members. Thirdly, an axially loaded concrete cylinder embedded with the smart rebar–aggregate is numerically and experimentally analyzed to investigate their performances of impedance monitoring. Additionally, empirical equations are formulated to represent the relationships between measured impedance signatures and applied compressive stresses. Lastly, an experimental test on a full-scale concrete anchorage embedded with smart rebar–aggregates at various locations is performed to evaluate the feasibility of the proposed method. For a sequence of loading cases, the variation in impedance responses is quantified to evaluate the accuracy of smart rebar–aggregate sensors. The empirical equations formulated based on the axially loaded concrete cylinder are implemented to predict compressive stresses at sensor locations in the PSC anchorage.
Journal Article